Astronomy Chpt 3

Front 1

In what ways do all humans use scientific thinking?

Back 1

Observations produce guesses. Guesses (hypotheses) are then tested against nature. Science is a way of learning about nature through careful observations and trial and error experiments – looking for patterns. We learn best like children, inducing “laws” but willing to revise if observations inconsistent with nature.

Front 2

How is modern science rooted in ancient astronomy?

Back 2

Practical Benefits of Astronomy: Moon “horns” predicted rainy seasons . Agriculture needed seasons predicted.

Astronomy and Measures of Time: Cycles of days (from Sun; “planets”), weeks, months (lunar), and years (seasons) are ancient.

Front 3

What did ancient civilizations achieve in astronomy?

Back 3

Determining the time of day: sundials, obelisks, Moon (ex. 1st quarter Moon sets at midnight), stars: rising-setting-crossing the meridian times and dates.

Days of the week named for 5 planets, Sun, Moon

Marking the Seasons:
Solar calendars: Stonehenge, Aztec, Chaco, Polynesian navigation
Lunar Calendars: 12 lunar months, Metonic cycle, etc.
Ancient structures and Archeoastronomy:
Were structures deliberate of coincidental? Ancestral Puebloans, Medicine wheels, Nazca lines,

From Observations to Science: How a culture used its astronomical knowledge depended on practical needs. Modern science emerged from the Middle East to Greece.

Front 4

Why does modern science trace its roots to the Greeks?

Back 4

1. Shifted from supernatural explanations
2. Used math to describe phenomena
3. Used reasoning (but not experiment)
Developed the idea of “models” to explain nature (conceptual representation to explain and predict observations)

Front 5

How did the Greeks explain planetary motion?

Back 5

Early Development of the Geocentric Model

Thales, Anaximander, Pythagoras, Plato, Eudoxus, Aristotle

Ptolemy’s Synthesis: adapted Eudoxus, Hipparchus, and Apollonius’ models of concentric circles to make it fit observed motions of planets. The “Almagest” used complicated deferent and epicycle circles.

Front 6

How was Greek knowledge preserved through history?

Back 6

Alexander, then Hypatia and the Library of Alexandria to 400 A.D. (constellation names)
Baghdad and the rise of Islamic culture to 1100. Saved and developed Greek works in math and science. (star names)
Western renaissance began with the fall of the Moors and Constantinople with captured Arabic works.

Front 7

How did Copernicus, Tycho, and Kepler challenge the Earth-Centered model?

Back 7

Copernicus: Alfonsine tables (Ptolemaic) complicated, (Alphonse’quote)so he tried updating Aristarchus’ heliocentric model and it was easier. Didn’t make better predictions (assumed circular orbits) so not immediately accepted.

Copernican Revolution: new world view.
Tycho: showed nova and comets were outside the Moon’s orbit. Made the best measures of planetary positions. This accurate data led to Kepler’s discovery of motion. The Tychonic model was
geocentric and not accepted.

Kepler: Using Tycho’s data he couldn’t make circular orbits work. Discovered elliptical orbits worked.
Ellipse, foci, semi-major axis, eccentricity. (trusted Tycho’s data)

Front 8

What are Kepler’s three laws of planetary motion?

Back 8

1. Planetary orbits are ellipses with the Sun a one focus (distance from a planet to the Sun varies)

2. Planets sweep out equal area in equal times (planet moves faster near the Sun than far away)

3. Size of orbit relates to period of orbit p2 = a3 (gives relative distances of planets from the Sun only)

Front 9

How did Galileo solidify the Copernican revolution?

Back 9

Answered the objections to heliocentric views of Aristotle.
1. Showed falling objects wouldn’t be left behind on a rotating Earth. (inertia)
2. Showed imperfections in the heavens. (sunspots, lunar craters, non-circular motion)
3. No parallax seen, but telescope showed stars more distant than thought.
Galileo’s Evidence:
Inertia: objects in motion don’t need an external force to keep moving. Objects won’t be left behind.
The Heavens’ are imperfect: sunspots, craters on Moon.
Full and gibbous phases of Venus contradict Ptolemy
Distant stars in MW didn’t prove parallax, but made distance great
Prediction of a Mercury transit showed Kepler was right.
Galileo suffered for his views from the inquisition. Heliocentric books unbanned 1757. Galileo vindicated 1992.
Sealing the case for heliocentric cosmology Galileo’s Observations of Jupiter and Venus. Venus can’t be gibbous in the Ptolemaic system

Front 10

How can we distinguish science from non-science?

Back 10

Science models are formulated, tested, and modified to fit data.

Science = “knowledge” is a recently coined word for what was “natural” philosophy. Scientific “method” rarely works as idealized. Not all science works the same way.

Front 11

What is a scientific theory?

Back 11

Theory: a hypothesis (model) that explains a wide variety of observations in terms of a few general principles. It makes predictions that survive repeated and varied tests.
Theories aren’t “proven”, but must have compelling evidence. Theories can only be replaced by ones that offer better explanations for observations. Sometimes a new theory causes a paradigm shift.
SCIENTIFIC THEORIES MUST BE FALSIFIABLE!!!
Logic in Science: Scientific theories are from inductive logic and go from specific to general, not deductive, from general to specific. However, both are useful in practice.
BUT !!! Nature is the final judge!!!!!!!!

Front 12

How is astrology different from astronomy?

Back 12

Astrology: played a historical role in the development of astronomy. Assumes the positions of Sun, Moon , and planets affect human events based on coincidences . It’s based on inductions that don’t predict reality.

Front 13

Does astrology have any scientific validity?

Back 13

Testing Astrology: astrological predictions show no predictive power over chance.
Underpinnings of Astrology: Constellations are chance alignments and changing over time. Sun and Moon affect some events (seasons, tides), but no scientific validity for affecting humans lives. What about Neptune or Pluto?
Pseudoscience: making claims that don’t test out.

Front 14

model

Back 14

is a conceptual representation created to explain and predict observed phenomena

Front 15

copernican revolution

Back 15

is in many ways the story of origin of modern science

Front 16

theory

Back 16

when a powerful yet simple model makes predictions that survive repeated and varied testing, scientists elevate its status and call it a _________

Front 17

paradigm

Back 17

Bias can sometimes show up even in the thinking of scientific community as a whole. some valid ideas may not be considered by any scientists because the ideas fall too far outside the general patterns of thought, or ___________

Front 18

astrology

Back 18

the basic tenet of astrology is that the apparent positions of the sun, moon, and planets among the stars in our sky influence human events

Front 19

pseudoscience

Back 19

means, "false science"